(negative square root two)/2, (negative square root two)/2
Answer:
0.1587
Step-by-step explanation:
Let X be the commuting time for the student. We know that
. Then, the normal probability density function for the random variable X is given by
. We are seeking the probability P(X>35) because the student leaves home at 8:25 A.M., we want to know the probability that the student will arrive at the college campus later than 9 A.M. and between 8:25 A.M. and 9 A.M. there are 35 minutes of difference. So,
= 0.1587
To find this probability you can use either a table from a book or a programming language. We have used the R statistical programming language an the instruction pnorm(35, mean = 30, sd = 5, lower.tail = F)
Due to the common probability formula I can solve that task. Refering to the task you gave, we have all the information we need. We solve it like that:

So the answer is the first option <span>
0.621%</span>
1/2 x > 0.4x
where Robert's spending is greater than Rosa's spending.
Allowance of Rosa = Allowance of Robert
let x = allowance
Rosa : video games = 0.4(x) ; pizza = 2/5 (x)
Robert : video games = 1/2 (x) ; pizza = 0.25 (x)
let us assume that their allowance is 100 each week. so, x = 100
Rosa : video games = 0.40(100) = 40
pizza 2/5 (100) = 200/5 = 40
total spending: 40 + 40 = 80
Robert : video games = 1/2 (100) = 50
pizza 0.25 (100) = 25
total spending: 50 + 25 = 75
Spending on video games
Rosa = 40
Robert = 50
Robert spent more of his allowance on video games than Rosa.
1/2 x > 0.4x